Keyed filter assembly

ABSTRACT

A filter assembly is disclosed including a cartridge member having a body portion and a cylindrical neck portion depending from the body portion, the neck portion having at least one lug depending radially outwardly therefrom having a keyed surface formation thereon, and a reception member defining an axial bore for receiving the neck portion of the cartridge member, the bore having at least one reception area provided therein for receiving the at least one lug, the reception area having a compatible mating surface formation defined therein for engaging the keyed surface formation on the lug so as to prevent engagement with an incompatible cartridge member.

The subject application is a divisional of Ser. No. 10/208,492 filedJul. 30, 2002, now abandoned, which is a continuation of U.S.application Ser. No. 09/553,982 filed Apr. 20, 2000, now U.S. Pat. No.6,458,269, and are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention relates to fluid filtration devices, and moreparticularly, to a filter assembly having a keyed lockout system toensure replacement cartridge compatibility.

2. Background of the Related Art

Commercial vending machines for dispensing liquids such as coffee orsoft drinks are wide spread in our society. It is common to filterliquids such as water in these vending machines before they aredispensed by circulating the water through an appropriate filter. It isalso commonplace to find filtering devices in consumer appliances suchas refrigerators for filtering drinking water and for ice production.Commercial and domestic filtering devices of this type have a limiteduseful life and require frequent replacement. Examples of prior artreplaceable filtering devices of this type are disclosed in commonlyassigned U.S. Pat. No. 4,735,716 to Petrucci et al. and U.S. Pat. No.4,806,240 to Giordano et al.

In most instances, the replaceable filters employed in commercial andconsumer appliances are manufactured in accordance with particulardesign specifications and performance parameters provided by theappliance manufacturer. In many cases, the filter media used in suchfilters consists of a proprietary material or is manufactured using aproprietary process. Thus, appliance manufactures often recommend thatreplacement cartridges be purchased from the original equipment providerso as to ensure the integrity and proper operation of the filteringsystem.

Oftentimes, the owner of a household appliance or the maintenancepersonnel servicing a commercial vending machine is not aware of thereplacement filter specifications and operating parameters of thefiltering system. Consequently, they unknowingly jeopardize theintegrity of the filtration system by replacing a used filter with aninferior or incompatible replacement filter supplied by an after-marketmanufacturer. This problem has also been encountered by automotivefilter manufacturers, as inferior replacement fuel filters arefrequently installed in a vehicle without the knowledge of the vehicleowner or operator.

One solution to this problem is disclosed in U.S. Pat. No. 5,035,797 toJanik, wherein a key system is provided to ensure replacement cartridgecompatibility for axially mounted fuel filters with threaded retainingcollars. The key system employs a unique matrix of axially projectingkeys formed in a base for axially receiving a filter cartridge, and acorresponding matrix of slots formed in a compatible cartridge, so thatfor a given compatible cartridge and base, the keys are interlockable inthe slots to securely lock the cartridge in the base. For eachnon-compatible cartridge and base, the base keys are not-mateable withthe cartridge slots and interfere with the mounting of the cartridge tothe base. A similar key system is disclosed in U.S. Pat. No. 5,186,829to Janik which includes a set of angularly spaced arcuate projectionsthat protrude radially from the cylindrical side wall of the fuel filtercartridge to mate with corresponding spaced apart recesses in the basewhen the cartridge is axially pushed into the base. U.S. Pat. No.5,837,137 to Janik discloses yet another key system for an axiallymounted fuel filter with a threaded retaining collar.

While such prior art key systems are suitable for use in conjunctionwith axially mountable automotive fuel filters having threaded retainingcollars, they are not easily adapted for use in conjunction withconsumer and industrial water filtration systems wherein the filtercartridge is provided with a set of cam lugs configured to facilitaterotatable mounting of the cartridge to a base or supporting structure.Examples of prior art filter cartridges having lugged engagementportions are disclosed in the Petrucci et al. and Giordano et al.patents discussed hereinabove, and in U.S. Pat. Nos. 4,857,189 and4,956,086 to Thomsen et al. It would beneficial to provide a key systemfor replaceable filter cartridges having lugged mounting systems.

SUMMARY OF THE INVENTION

The subject invention is directed to a unique filter assembly forensuring replacement cartridge compatibility in filtration systemshaving replaceable filter cartridges with lugged mounting systems. Inaccordance with a preferred embodiment of the subject invention, thefilter assembly comprises a cartridge member including a body portionand a cylindrical neck portion which depends from the body portion. Theneck portion has a pair of diametrically opposed lugs depending radiallyoutwardly therefrom, wherein each lug has an engagement surface defininga keyed surface formation. The neck portion has an inlet passage fordelivering fluid into the body portion and an outlet passage fordelivering fluid from the body portion.

The filter assembly further comprises a head member defining an axialbore and having a fluid inlet port to accommodate the ingress of fluidinto the axial bore and a fluid outlet port to accommodate the egress offluid from the axial bore. A rotary valve member is disposed within theaxial bore of the head member and defines an axial bore for receivingthe neck portion of the cartridge member. The axial bore of the valvemember has a pair of diametrically opposed reception areas definedtherein for receiving the lugs of the neck portion. Each reception areahas a mating surface defining a keyed surface formation adapted andconfigured to mate with the keyed surface formation of a correspondinglug of a compatible filter cartridge. In addition, the valve member hasan inlet orifice for communicating with the inlet port of the headmember and an outlet orifice for communicating with the outlet port ofthe head member when the lugs of the neck portion are engaged with thereception areas of the valve member and the valve member is rotated intoan operational position.

The filter assembly further comprises a support member disposed betweenthe valve member and the cartridge member. The support member has anaperture extending therethrough for receiving and retaining the neckportion of the cartridge member and a seating area for receiving andretaining the head member. Preferably, each lug includes an inclined camsurface on a lower portion thereof for cooperating with a pair ofdiametrically opposed cam ramps projecting into the aperture of thesupport member. In use, rotation of the cartridge member relative to thesupport member effectuates rotational movement of the valve memberrelative to the head member.

In accordance with a preferred embodiment of the subject invention, thekeyed surface formation on each lug includes a plurality of spaced aparttooth positions each for accommodating an axially projecting tooth, andthe recessed areas include a series of spaced apart recesses for matingwith the axially projecting teeth of a compatible filter cartridge.Alternative keyed surface formations and corresponding reception areasare also envisioned and are disclosed herein.

The subject invention is also directed to a filter assembly thatcomprises a filter cartridge including a body portion and a cylindricalneck portion depending from the body portion, wherein the neck portionhas at least one lug depending radially outwardly therefrom having akeyed surface formation thereon, and a reception member defining anaxial bore for receiving the neck portion of the cartridge member, thebore having at least one reception area provided therein for receivingthe at least one lug, wherein the reception area has a compatible matingsurface formation defined therein for engaging the keyed surfaceformation on the lug so as to prevent engagement with an incompatiblefilter cartridge. The reception member is preferably defined by a rotaryvalve disposed within an interior bore of a housing member or an annularinsert disposed within an interior bore of a housing member.

In accordance with a preferred embodiment the subject invention, thereis also disclosed a filter cartridge system that comprises a set offilter cartridges each including a cylindrical neck portion, the neckportion of each filter cartridge in the set having at least one lugdepending therefrom with a keyed surface formation thereon to enable thecartridge to mate with a compatible reception member, wherein eachfilter cartridge in the set has a different keyed surface formationthereon.

These and other unique features of the lenticular filter cartridgeassembly of the subject invention and the method of constructing thesame will become more readily apparent from the following description ofthe drawings taken in conjunction with the detailed of the preferredembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those having ordinary skill in the art to which the subjectinvention appertains will more readily understand how to construct anduse the filter cartridge assembly of the subject invention, referencemay be had to the drawings wherein:

FIG. 1 is a perspective view of a filter assembly constructed in aaccordance with a preferred embodiment of the subject invention;

FIG. 2 is an exploded perspective view of the filter assembly of FIG. 1with part separated for ease of illustration;

FIG. 3 is an enlarged perspective view of the upper portion of thefilter assembly of FIG. 1 including the filter cartridge, supportbracket and head member;

FIG. 4 is a cross-sectional view of the support bracket shown in FIG. 3taken along line 4—4 of FIG. 3 illustrating the ramped camming surfaceformed thereon;

FIG. 5 is bottom end view of the valve member shown in FIG. 3 as viewedalong line 5—5 of FIG. 3;

FIG. 6 is an elevational view of the valve member of FIG. 3, with aportion of the outer wall broken away to illustrate interior surfacefeatures thereof;

FIG. 7 is an elevational view of the valve member of FIG. 3, with aportion of the outer wall broken away and rotated 180° from the positionshown in FIG. 6 to illustrate interior surface features thereof;

FIG. 8 is an elevational view of the upper portion of the filtercartridge and the valve member of FIG. 3, with the interlocking featuresthereof in axial alignment to facilitate the engagement therebetween;

FIG. 9 is an elevational view of the upper portion of the filtercartridge and the head member of FIG. 3, rotated 180° from the positionshown in FIG. 8, with the interlocking features thereof in axialalignment to facilitate the engagement therebetween;

FIG. 10 is a perspective view of the upper portion of the filterassembly of the subject invention, with the wall of the head and valvemembers broken away to illustrate the initial position of the keyedcamming lug of the filter relative to the ramped camming surface of thebracket member, wherein the valve assembly with which the head member isassociated is closed to flow;

FIG. 11 is a perspective view of the upper portion of the filterassembly of the subject invention, with the wall of the head memberbroken away to illustrate the final position of the keyed camming lug ofthe filter relative to the ramped camming surface of the bracket member,wherein the valve assembly with which the head member is associated isopen to flow;

FIG. 12 is a perspective view of the cylindrical neck portion of thefilter cartridge of the subject invention which includes camming lugshaving a skeleton key formation;

FIGS. 13–17 illustrate a variety of different key configurationsprovided on the camming lugs formed on the cylindrical neck portion ofthe filter cartridge of the subject invention;

FIGS. 18–20 illustrate each of the available key patterns for a camminglug having a maximum of four teeth positions;

FIGS. 21–27 illustrate each of the available key patterns for a camminglug having a maximum of five teeth positions;

FIGS. 28–40 illustrate each of the available key patterns for a camminglug having a maximum of six teeth positions;

FIG. 41 is a top plan view of the neck portion of a filter cartridgeconstructed in accordance with a preferred embodiment of the subjectinvention which includes three circumferentially spaced camming lugseach having a different key formation thereon;

FIG. 42 is a side elevational view of the neck portion of the filtercartridge of FIG. 41, taken along line 42—42;

FIG. 43 is a side elevational view of the neck portion of the filtercartridge of FIG. 41, rotated 120° from the view shown in FIG. 42;

FIG. 44 is a side elevational view of the neck portion of the filtercartridge of FIG. 41, rotated 120° from the view shown in FIG. 43;

FIG. 45 is a top plan view of the neck portion of a filter cartridgeconstructed in accordance with a preferred embodiment of the subjectinvention which includes two sets of diametrically opposed camming lugspositioned at two different levels on the neck portion of the cartridge;

FIG. 46 is a side elevational view of the neck portion of the filtercartridge of FIG. 45, taken along line 46—46;

FIG. 47 is a side elevational view of the neck portion of the filtercartridge of FIG. 45, rotated 90° from the view shown in FIG. 46;

FIG. 48 is a side elevational view of the neck portion of the filtercartridge of FIG. 45, rotated 90° from the view shown in FIG. 47;

FIG. 49 is a side elevational view of the neck portion of the filtercartridge of FIG. 45, rotated 90° from the view shown in FIG. 48;

FIG. 50 is a side elevational view in cross-section, of another filterassembly constructed in accordance with a preferred embodiment of thesubject invention wherein a ball valve is positioned within the assemblyto inhibit the egress of fluid from the system when the filter cartridgeis removed from the assembly, with the ball valve shown in an openposition;

FIG. 51 is a side elevational view in cross-section, of the filterassembly of FIG. 50 with the ball valve shown in a closed position asthe filter cartridge is removed from the assembly;

FIG. 52 is an exploded perspective view of another filter assemblyconstructed in accordance with a preferred embodiment of the subjectinvention with the parts thereof separated for ease of illustration,including an annular insert in the form of a key ring having recessesdesigned to mate with corresponding surface features on the keyed camlugs of a replacement filter cartridge; and

FIG. 53 is a perspective view of the filter assembly of the FIG. 52 withthe head portion in cross-section to illustrate the interior structurethereof.

These and other features of the filter assembly of the subject inventionwill become more readily apparent to those having ordinary skill in theart form the following detailed description of the preferredembodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the figures wherein like reference numerals identifysimilar structural elements of the filter assembly of the subjectinvention, there is illustrated in FIG. 1 a filter assembly constructedin accordance with a preferred embodiment of the subject invention anddesignated generally by reference numeral 10. Filter assembly 10 isconfigured for use in conjunction with a fluid processing system thatincludes an inlet conduit 12 for delivering unfiltered process fluidinto the filter assembly and an outlet conduit 14 for deliveringfiltered process fluid from the filter assembly 10. Filter assembly 10is preferably mounted to a supporting structure associated with thefluid processing system by a bracket 16.

Referring to FIG. 2, filter assembly 10 includes a unique rotary valveassembly 18 that consists of a head portion 20 defining an interiorchamber having an inlet port 22 for communicating with inlet conduit 12and an outlet port 24 for communicating with outlet conduit 14. Rotaryvalve assembly 18 further includes a valve member 26 configured forreception within the interior chamber of head portion 20 in such amanner so as to facilitate rotation of the valve member relative to thehead portion between an open position wherein fluid is permitted to flowthrough the filter assembly and a closed position wherein flow throughthe filter assembly is restricted. (See FIGS. 10–11).

Valve member 26 includes an inlet orifice 32 for communicating with theinlet port 22 of head portion 20 and an outlet orifice 34 forcommunicating with the outlet port 24 of head portion 20. (See FIGS.6–7). The body of valve member 26 includes recesses 36 a and 38 a foraccommodating upper and lower O-ring seals 36 and 38. O-ring seal 36serves to sealingly isolate the inlet flow from the outlet flow withinthe interior chamber of head portion 20 during operation, while O-ringseal 38 prevents leakage to atmosphere.

With continuing reference to FIG. 2, filter assembly 10 further includesa replaceable filter cartridge 40 constructed in accordance with apreferred embodiment of the subject invention. Filter assembly 10 isadapted and configured to ensure that replacement cartridge 40 iscompatible with the fluid processing system with which it is associated.Moreover, as discussed hereinbelow, the filter cartridge 40 and headportion 20 are provided with keyed mating structures that ensurecompatibility therebetween, and thus prevent the accidental orintentional installation of an incompatible or inferior replacementcartridge, which could jeopardize the integrity of the fluid processingsystem.

Referring to FIG. 3, replaceable filter cartridge 40 includes agenerally cylindrical body portion 42 enclosing filter media forfiltering process fluid. Those skilled in the art will readilyappreciate that any one of a variety of different types of filter mediacould be enclosed within the body portion including, for example,pleated media, micro-fibers or carbon media. An end cap 44 encloses thebody portion 42, and a cylindrical neck portion 46 depends from the endcap 44. Those skilled in the art will readily appreciate that the endcap 44 and body portion 42 can be joined together by sonic welding, spinwelding or other similar methods known in the art. Accordingly, the bodyportion and the neck portion are operably connected such that one is notseparable from the other. The neck portion 46 of filter cartridge 40 isadapted and configured for reception with the interior cavity of valvemember 26 (see FIGS. 6–9) and includes an upper section 46 a and a lowerportion 46 b.

The upper section 46 a defines a radial inlet passage 52 for receivingunfiltered process fluid entering the valve member 26 through inletorifice 32 and directing the fluid into the body portion 42 of filtercartridge 40. The upper section 46 a further defines an axial outletpassage 54 for delivering filtered process fluid from the interior ofbody portion 42 to the interior cavity of valve member 26 for egressthrough the outlet orifice 34 into the interior chamber of head portion20. Those skilled in the art will readily appreciate that the inlet andoutlet passages in the neck portion could be reversed such that theinlet flow is axial and the outlet flow is radial. The inlet and outletpassages 52 and 54 are sealingly isolated from one another by an upperO-ring seal 56 positioned at the upper end of neck portion 46. A secondlower O-ring seal 58 is positioned below the radial inlet passage 52 tosealingly engage the neck portion 46 within the interior chamber of thevalve member 26 and prevent the leakage of unfiltered process fluidsfrom filter assembly 10 while in operation.

Referring to FIG. 2 in conjunction with FIG. 3, a pair of diametricallyopposed inclined cam lugs 62 and 64 project radially outwardly from thelower section 46 b of neck portion 46. Cam lugs 62 and 64 aredimensioned and configured to facilitate rotational engagement of thefilter cartridge within an intermediate support flange 70 that dependsfrom mounting bracket 16. As best seen in FIG. 3, a central aperture 75extends through support flange 70 for receiving the neck portion 46 offilter cartridge 40. A pair of diametrically opposed cam ramps 72 and 74project radially into central aperture 75 for interacting with theinclined lower surfaces of cam lugs 62 and 64 that are axially spacedfrom the body portion and face toward the body portion in a generallyaxial direction. The cam ramps 72 and 74 are spaced from one another toallow the cam lugs 62 and 64 to fit therebetween when the neck portionis extended through aperture 75 during assembly, and they are inclinedalong their arc length to facilitate rotational engagement of the filtercartridge with support flange 70, as illustrated in FIG. 4.

Referring to FIGS. 2 and 3, support flange 70 further includes arecessed seating area 76 defined by annular retaining wall 78 andconfigured to receive and retain the head portion 20 of filter assembly10. Diametrically opposed arcuate retention ribs 82 and 84 projectinwardly from retaining wall 78 to frictionally engage withcorresponding ramped engagement struts 92 and 94 that project radiallyoutwardly from the lower region of head portion 20 when the head portion20 is rotatably engaged within the recessed seating area 76 duringassembly. Stop surfaces 82 a and 84 a are associated with retention ribs82 and 84, respectively, for limiting the movement of head portion 20within seating area 76. In an alternate embodiment, the head portion 20and support flange 70 may be adapted and configured to cooperate andengage with one another in a manner described hereinbelow with respectto filter assembly 800 and illustrated in FIGS. 52–53.

As best seen in FIGS. 1 and 2, the annular retaining wall 78 of supportflange 70 is also configured to accommodate and support a shroud 90which is configured to house and protect the rotary valve assembly 18 offilter assembly 10. As illustrated, the shroud 90 includes lateralapertures, i.e., aperture 92, for accommodating inlet and outletconduits 12 and 14. Those skilled in the art will readily appreciatethat the configuration of the shroud as well as the way in which it isjoined to the support flange 70 could vary depending upon the nature ofthe operating environment within which the system is employed.

Referring to FIG. 5, in accordance with a preferred embodiment of thesubject invention, cam lugs 62 and 64 are adapted and configured forreception within a pair of corresponding diametrically opposed receptionareas 102 and 104 formed within the interior cavity 25 of valve member26. Each of the lugs has engagement surfaces which face away from thebody portion. At least one of the engagement surfaces defines a keyedsurface formation including at least one tooth or protrusion axiallyextending from remaining portions of the engagement surfaces relative tothe neck which enables the cartridge to mate with a compatible receptionassembly. More particularly, the upper surface of each cam lug 62, 64 isprovided with a unique key formation having, in this case, a pluralityof spaced apart axially projecting teeth that are adapted and configuredto engage and mate with a corresponding set of spaced apart recessesformed within the reception areas of the valve member 26. This matingarrangement is designed to ensure replacement cartridge compatibility byonly permitting replacement of a filter cartridge having a keyed surfaceformation that corresponds with the surface features of the receptionareas in the valve member.

In the exemplary embodiment of the invention illustrated in FIGS. 3–9,the key formation on each cam lug (62, 64) includes three spaced apartteeth (62 a–62 c, 64 a–64 c) and each reception area (102, 104) withinthe valve member 26 includes three corresponding recesses (102 a–102 c,104 a–104 c) for accommodating the teeth when the neck portion 46 ofcartridge 40 is received by valve member 26.

As discussed in greater detail hereinbelow, the number of teeth thatdefine the key formation on each cam lug can vary within the scope ofthis invention (see for example FIGS. 18–40), as can the surfacegeometry of the key formation (see for example FIGS. 13–17). In eachinstance, the reception area in the rotary valve member would have acorresponding mating configuration to accommodate the key formationformed on the cam lugs. Furthermore, it is envisioned that the keyconfiguration on one lug could be substantially similar to or differentfrom the key configuration of the opposed lug. This will dramaticallyincrease the number of possible key combinations available to a filtermanufacturer.

Referring to FIG. 10, when a compatible filter cartridge is introducedinto the filter assembly 10 of the subject invention, the neck portion46 of the filter cartridge 40 is inserted through the central aperture75 of support flange 70, with the cam lugs 62 and 64 positioned betweenthe diametrically opposed cam ramps 72 and 74. At such a time, the valvemember 26 is in the “off” position to receive the neck portion 46. Thus,the inlet and outlet orifices 32, 34 of valve member 26 are not alignedwith the inlet and outlet ports 42, 44 of head portion 20. Thereupon,the teeth (62 a–62 c, 64 a–64 c) forming the keyed engagement surface ofcam lugs 62 and 64 extend into the corresponding recesses (102 a–102 c,104 a–104 c) of recessed areas 102 and 104 and mate therewith.

Once the neck portion 46 of filter cartridge 40 has been intimatelyengaged within the interior chamber of valve member 26, the cartridgeand valve member may rotated in a counter-clockwise direction withrespect the support flange 70 and head portion 20, as illustrated inFIG. 11. Upon rotating filter cartridge 40 in conjunction with valvemember 26, the cam lugs 62, 64 projecting from neck portion 46 translateagainst the cam ramps 72, 74, causing the filter cartridge 40 to movehelically upwardly in an axial direction. As a result, valve member 26is rotated into the “on” or open position, wherein the inlet and outletorifices 32, 34 of the valve member 26 are aligned with the inlet andoutlet ports 42, 44 of head portion 20 to allow fluid to flow throughthe filter assembly 10.

If the cam lugs of a replacement filter cartridge introduced into thesystem are not configured to mate with the reception areas of the valvemember, i.e., if the cam lugs have no keyed surface formation, which maybe indicative of an unauthorized after-market filter cartridge, the camlugs will interfere with and be unable to engage the reception areas inthe valve member. Consequently, because the inclined cam surfaces of thecam lugs 62, 64 will be located below the inclined surfaces of the camramps 72, 74, the cam lugs will be unable to traverse the cam ramps. Asa result, the cam lugs will be unable to effect rotation of the valvemember into the “on” position to permit fluid to flow through theassembly. This will ensure replacement cartridge compatibility bypreventing the use of inferior or unauthorized replacement filtercartridges.

The key formation shown in the exemplary embodiment of FIGS. 3–11,corresponds to the key formation illustrated in FIG. 21, which isselected from a group of key formations having five available toothpositions. In the exemplary embodiment, the first, fourth and fifthteeth are present, while the second and third teeth are absent. Usingthe convention wherein the numeral “1” represents the presence of atooth in a position of a key formation, and the numeral “0” representsthe absence of a tooth in a position of the key formation, the keyformation illustrated in FIGS. 3–11, and 21 may be represented by thenumerical expression (1, 0, 0, 1, 1).

In accordance with a preferred embodiment of the subject invention,there exists a replacement cartridge that is provided with cam lugshaving a surface formation that is compatible with a rotary valve memberregardless of the number of recesses defined within the recessed areasformed therein. A cartridge having a neck portion with diametricallyopposed cam lugs that include such a formation, referred to herein as askeleton key formation, is illustrated in FIGS. 2 and 12 and isdesignated generally by reference numeral 140.

Referring to FIG. 12, the cam lugs 162 and 164 of filter cartridge 140includes a skeleton key formation defined by a tooth formation whereinonly the first and fifth tooth positions are filled with teeth (i.e.,teeth 162 a, 162 b). This skeleton key is represented by the numericalexpression (1, 0, 0, 0, 1). It should be understood that, in a fiveposition key formation, the first and fifth position will always befilled, and, conversely, the recessed areas of the valve member willalways have a recess located in the complementary positions.

Table 2 below, sets forth the available tooth combinations for the fiveposition key formation associated with the opposed cam lugs 162 and 164of filter cartridge 140 and illustrated in FIGS. 3–11 and 21–27. Intotal, excluding the skeleton key formation of FIG. 12, there are sevenavailable tooth configurations for a five position key formation. Table1 below sets forth the available tooth configurations for the fourposition key formation associated with the opposed cam lugs 262 and 264of filter cartridge 240 illustrated in FIGS. 18–20. In total, excludingthe skeleton key formation which is not shown and is represented by thenumerical expression (1, 0, 0, 1) there are three available toothconfigurations for a four position key formation. Table 3 sets forth theavailable tooth configurations for the six position key formationassociated with the opposed cam lugs 362 and 364 of replaceable filtercartridge 340 as illustrated in FIGS. 28–41. In total, excluding theskeleton key formation which is not shown and is represented by thenumerical expression (1, 0, 0, 0, 0, 1) there are fifteen availabletooth configurations for a six position key formation.

TABLE 1 Tooth Configurations (Four Positions) FIG. 1, 1, 1, 1 18 1, 1,0, 1 19 1, 0, 1, 1 20

TABLE 2 Tooth Configurations (5 positions) FIG. 1, 1, 1, 1, 1 21 1, 0,0, 1, 1 22 1, 0, 1, 0, 1 23 1, 1, 0, 1, 1 24 1, 1, 1, 0, 1 25 1, 0, 1,1, 1 26 1, 1, 0, 0, 1 27

TABLE 3 Tooth Configurations (6 positions) FIG. 1, 1, 1, 1, 1, 1 28 1,1, 0, 0, 0, 1 29 1, 1, 1, 0, 0, 1 30 1, 1, 1, 1, 0, 1 31 1, 0, 0, 0, 1,1 32 1, 0, 0, 1, 1, 1 33 1, 0, 1, 1, 1, 1 34 1, 1, 0, 0, 1, 1 35 1, 1,0, 1, 1, 1 36 1, 1, 1, 0, 1, 1 37 1, 0, 1, 1, 0, 1 38 1, 1, 0, 1, 0, 139 1, 0, 1, 0, 1, 1 40 1, 0, 1, 0, 0, 1 not shown 1, 0, 0, 1, 0, 1 notshown

In sum, the number of available tooth combinations “N” for a given toothconfiguration having “n” tooth positions can be expressed mathematicallyas follows:N=2^(n−2)−1

The relatively large number of key configuration that are availablethough the keyed system of the subject invention will give originalequipment manufactures the ability to provide customized filters foreach of their appliances. Thus, each manufacturer could offer a uniqueset of replacement filter cartridge, with each cartridge in the sethaving a different keyed surface formation provided on the camming lugsthereof, for mating with corresponding reception areas in a valve membersupported within a particular type of appliance.

Referring to FIGS. 13–17, there are illustrated a series of replacementfilter cartridges constructed in accordance with a preferred embodimentof the subject invention each having a different keyed surface formationassociated therewith. For example, FIGS. 13, 14, 16 and 17 illustratefilter cartridges 403, 404, 406, and 407, respectively, with cam lugs463, 464, 466 and 467 having keyed surface formations with portions thatproject both radially outwardly from the lugs as well as in an axialdirection. For example, cam lug 463 in FIG. 13 includes two teeth 463 a,463 b which project axially and radially from the lug. Cam lug 464 inFIG. 14 includes two axially projecting teeth 464 a and 464 c and onetooth 464 b that projects both radially and axially. FIG. 16 illustratesa cam lug 466 having an enlarged radially and axially projecting tooth466 a and a smaller axially projecting tooth 466 b. Cam lug 467 in FIG.17 includes two axially projecting teeth 467 a and 467 b and themajority of the cam lug itself project radially outwardly from the neckportion of the filter cartridge 407. In accordance with the subjectinvention, it follows that a compatible rotary valve member would haverecessed areas with mating features that correspond to the radially andaxially extending keyed surface formations of cam lugs 463, 464, 466 and467.

FIG. 15, illustrates another replacement filter cartridge 405constructed in accordance with a preferred embodiment of the subjectinvention wherein the keyed surface formation provided on the cam lug465 thereof is defined by a curved surface 465 a. In accordance with thesubject invention, a compatible valve member for filter cartridge 405would have reception areas with a corresponding curved recesses toensure compatibility with cartridge 405.

Referring to FIG. 41–44, there is illustrated another replacement filtercartridge constructed in accordance with a preferred embodiment of thesubject invention and designated generally by reference numeral 540.Filter cartridge 540 includes three cam lugs 561, 562 and 563 that arecircumferentially spaced apart about the periphery of neck portion 546.Each cam lug has a keyed surface formation thereon for mating with acorresponding recessed area of a compatible rotary valve member 26. Asillustrated in FIGS. 42–44, the keyed surface formations of cam lugs561–563 are derived from a five tooth configuration (see Table 2), andeach cam lug has a different key pattern formed thereon. In particular,cam lug 561 has a first keyed surface formation that may be representedby the numerical expression (1, 0, 1, 0, 1), cam lug 562 has a secondkeyed surface formation that may be represented by the numericalexpression (1, 0, 0, 1, 1), and cam lug 563 has a third keyed surfaceformation that may be represented by the numerical expression (1, 1, 0,0, 1). It is also envisioned that cam lugs 561–563 could each have thesame keyed surface formation provided thereon.

Referring to FIG. 45–49, there is illustrated another replacement filtercartridge constructed in accordance with a preferred embodiment of thesubject invention and designated generally by reference numeral 640.Filter cartridge 640 includes two sets of diametrically opposed cam lugsthat include cam lugs 661–664. The first set of opposed cam lugs 661,663 are positioned at a first axial height on neck portion 646, and thesecond set of opposed cam lugs 662, 664 are positioned at a second axialheight on neck portion 646. In addition, each cam lug has a keyedsurface formation thereon for mating with a corresponding recessed areaof a compatible rotary valve member 26. As illustrated in FIGS. 46–49,the keyed surface formations of cam lugs 661–664 are derived from a fivetooth configuration (see Table 2). Cam lugs 661 and 664 have the samekeyed surface formation thereon that may be represented by the numericalexpression (1, 0, 0, 1, 1), while cam lugs 662 and 663 both have anotherkeyed surface formation thereon that may be represented by the numericalexpression (1, 1, 0, 0, 1). It is also envisioned that cam lugs 661–664could each have the same keyed surface formation provided thereon, or,in the alternative, each cam lug could have a different keyed surfaceformation provided thereon.

Referring to FIGS. 50–51, there is illustrated another filter assemblyconstructed in accordance with a preferred embodiment of the subjectinvention and designated generally by reference numeral 700. Filterassembly 700 includes a head portion 720 enclosing a rotary valve member726 that has a mechanism for minimizing leakage during cartridgereplacement. The mechanism includes a floating check-ball 728 and anassociated valve seat 730. As shown in FIG. 51, during normal service,when process fluid is flowing through the system, the outlet flowpressure of the filtered fluid causes the check-ball 728 to remain in anunseated position. In contrast, when the neck portion 46 of areplacement filter cartridge 40 is removed from the interior bore ofvalve member 726, and the outlet flow pressure is terminated, thecheck-ball 728 becomes seated in valve seat 730, as shown in FIG. 51. Asa result, the void volume within head portion 720 is restricted fromflowing out of valve member 726.

Referring now to FIGS. 52–53, there is illustrated another filterassembly constructed in accordance with a preferred embodiment of thesubject invention and designated generally by reference numeral 800.Filter assembly 800 differs from the previously described embodiments ofthe subject invention in that the assembly does not include a rotaryvalve member, such as the valve member 18 of filter assembly 10.Instead, as best seen in FIG. 53, filter assembly 800 includes a headportion 820 with an interior bore 825 having a lower region 825 aconfigured to support an annular insert in the form of a key ring 818.Key ring 818 defines diametrically opposed reception areas 802, 804 formating with corresponding keyed surface formations on the cam lugs 62,64 formed on the neck portion 26 of a replacement filter cartridge 40,for example. In accordance with the subject invention, to ensure theintegrity of the system with which filter assembly 800 is associated, acompatible replacement cartridge must have cam lugs with keyed surfaceformations that mate with the recessed areas of the key ring 818.

Referring to FIG. 52, filter assembly 800 further includes a mountingbracket 816 having a support flange 870 depending therefrom forfacilitating rotational engagement of a replacement filter cartridge 40with head member 820 and the associated key ring 818. A central aperture875 extends through support flange 870 to receive the neck 46 of filtercartridge 40, and a pair of diametrically opposed cam raps 872 and 874project radially into central aperture 875 for operatively interactingwith the inclined lower surfaces of cam lugs 62, 64 when filtercartridge 40 is engage with head portion 820.

Support flange 870 further includes a recessed seating area 876 definedby an annular retaining wall 878 configured to receive and retain thehead portion 820. More particularly, head portion 820 includes a pair ofdiametrically opposed ramped cam struts 882 and 884 for operativelyengaging a pair of diametrically opposed retention flanges 892 and 894projecting radially inwardly from the retaining wall 878. In addition,ratchet nibs 882 a and 884 a project outwardly from the lower region ofhead portion 820 for engagement within corresponding notches 892 a and894 a formed in retention flanges 892 and 894, respectively. Thoseskilled in the art will readily appreciate that the way in which headportion 820 and support flange 870 interact and engage may also beemployed in conjunction with the filter assembly 10 describedhereinabove, whereby head portion 20 and support flange 70 would beadapted and configured to interact and engage in a substantially similarmanner.

To assemble the filter assembly 800 of the subject invention, a key ring818 having particular configuration of recesses, which may be selectedfrom a set of key rings each having different recess configurations, isfirst inserted into the lower region 825 a of interior bore 825 of headpotion 820. The head portion is then rotatably engaged within theseating area 876 of support flange 870. Thereafter, a filter cartridge40 is brought into approximation with the head portion 820 by insertingthe neck portion 46 of the cartridge through the central aperture 875 ofsupport flange 870, allowing the camming lugs 62, 64 to pass between theopposed cam ramps 872, 874 projecting radially into aperture 875. Atsuch a time, the keyed surface formations of the cam lugs 62, 64 matewith the corresponding recessed areas 802, 804 in key ring 818, providedof course that the cartridge and key ring are compatible with oneanother. Once the cam lugs 62, 64 are mated with the recessed areas 802,804, the filter cartridge 40 is rotated through an arc of approximately90°, such that the inclined lower surfaces of cam lugs 62, 64 translaterelative to cam ramps 872, 874. This relative movement causes the keyring 818 to rotate within interior bore region 825 a and causes the neckportion 46 of filter cartridge 40 to move axially into the upper region825 b of the interior bore 825 of head portion 820, until such time asthe neck portion of the filter cartridge is sealingly received therein.

It should be noted that provision is made such that key ring 818 willrotate through a limited travel range relative to the head portion 820as filter cartridge 40 is rotated into engagement with head portion 820.Furthermore, since a rotary valve member is not utilized with headportion 820, the upper region 825 b of interior bore 825 is dimensionedand configured to directly mate with the neck portion 46 of filtercartridge 40, such that the inlet port 52 in neck portion 46 is indirect fluid communication with the radial inlet port 812 of headportion 820 and the axial outlet port 54 in neck portion 46 is in directfluid communication with the radial outlet port 814 of head portion 820.

Although the disclosed fluid filtration apparatus has been describedwith respect to preferred embodiments, it is apparent that modificationsand changes can be made thereto without departing from the spirit andscope of the invention as defined by the appended claims.

1. A filter cartridge comprising: a body portion for enclosing filtermedia for filtering a fluid; and a neck portion including an inlet portfor directing unfiltered fluid into the body portion and an outlet portfor directing filtered fluid out of the body portion, the body portionand the neck portion being operably connected such that one is notseparable from the other, the neck portion having at least two lugsdepending radially outwardly therefrom, each lug having engagementsurfaces which face away from the body portion, wherein each lug has aninclined cam surface axially spaced from the body portion and facingtoward the body portion in a generally axial direction for cooperatingwith camming ramps on a compatible reception assembly, at least one ofthe engagement surfaces defining a keyed surface formation comprising:at least one tooth extending axially from remaining portions of theengagement surfaces relative to the neck, the at least one toothenabling the cartridge to mate with a compatible reception assembly andpreventing the cartridge from mating with an incompatible receptionassembly.
 2. A filter cartridge as recited in claim 1, wherein each lughas an engagement surface defining a keyed surface formation.
 3. Afilter cartridge as recited in claim 2, wherein the keyed surfaceformation on each lug of the cartridge is substantially similar.
 4. Afilter cartridge as recited in claim 2, wherein the keyed surfaceformation on each lug of the cartridge is different.
 5. A filtercartridge as recited in claim 1, wherein the neck portion has a pair ofdiametrically opposed lugs.
 6. A filter cartridge as recited in claim 1,wherein the neck portion has three circumferentially spaced apart lugs.7. A filter cartridge as recited in claim 1, wherein the neck portionhas first and second pairs of diametrically opposed lugs, wherein thefirst pair of lugs is disposed at a first height on the neck portion andthe second pair of lugs is disposed at a second height on the neckportion.
 8. A filter cartridge as recited in claim 1, wherein the keyedsurface formation is on an axially facing engagement surface of the lug.9. A filter cartridge as recited in claim 1, wherein the keyed surfaceformation is on a radially facing engagement surface of the lug.
 10. Afilter cartridge as recited in claim 1, wherein at least a first portionof the keyed surface formation is on an axially facing engagementsurface of the lug and at least a second portion of the keyed surfaceformation is on a radially facing engagement surface of the lug.
 11. Afilter cartridge comprising: a body portion for enclosing filter mediafor filtering a fluid; and a neck portion including an inlet port fordirecting unfiltered fluid into the body portion and an outlet port fordirecting filtered fluid out of the body portion, the body portion andthe neck portion being operably connected such that one is not separablefrom the other, the neck portion having at least two lugs dependingradially outwardly therefrom, each lug having radial and axialengagement surfaces facing away from the body portion, wherein each lughas an inclined cam surface axially spaced from the body portion andfacing toward the body portion in a generally axial direction forcooperating with camming ramps on a compatible reception assembly, atleast one of the engagement surfaces defining a keyed surface formationcomprising: at least one protrusion extending axially from remainingportions of the engagement surfaces relative to the neck, the at leastone protrusion enabling the cartridge to mate with a compatiblereception assembly and preventing the cartridge from mating with anincompatible reception assembly.
 12. A filter cartridge as recited inclaim 11, wherein each lug has an engagement surface defining a keyedsurface formation.
 13. A filter cartridge as recited in claim 12,wherein the keyed surface formation on each lug of the cartridge issubstantially similar.
 14. A filter cartridge as recited in claim 12,wherein the keyed surface formation on each lug of the cartridge isdifferent.
 15. A filter cartridge as recited in claim 11, wherein theneck portion has a pair of diametrically opposed lugs.
 16. A filtercartridge as recited in claim 11, wherein the neck portion has threecircumferentially spaced apart lugs.
 17. A filter cartridge as recitedin claim 11, wherein the neck portion has first and second pairs ofdiametrically opposed lugs, wherein the first pair of lugs is disposedat a first height on the neck portion and the second pair of lugs isdisposed at a second height on the neck portion.
 18. A filter cartridgeas recited in claim 11, wherein the keyed surface formation is on theaxial engagement surface of the lug.
 19. A filter cartridge as recitedin claim 11, wherein the keyed surface formation is on the radialengagement surface of the lug.
 20. A filter cartridge as recited inclaim 11, wherein at least a first portion of the keyed surfaceformation is on the axial engagement surface of the lug and at least asecond portion of the keyed surface formation is on the radialengagement surface of the lug.